Equipment for facilitating research and performing production processes in biochemical related industries is part of a rapidly expanding marketplace. Conducting chemical reagents, solvents, and other fluids, often in small conduits and tubings and at low flow rates under low pressure, is often required in such equipment, and there is a need for valves that can be remotely actuated for automatic control. There is also a need for such valving to be manifolded so a number of different fluids may be switched into various lines to and from reaction chambers and the like. To be useful in the industry (particularly where there is direct contact with samples for analysis and other fluids used in the chemical processes), it is necessary that the materials for such manifolds and valves be inert to the fluids used, which are quite varied. Examples of equipment of this nature are the protein sequencers and DNA synthesizers marketed by Applied Biosystems Inc. of Foster City Calif.; some of these systems are shown in the following publications of Applied Biosystems Inc.: 430A Service Manual, 340A Service Manual, 380A Service Manual, and 470A Service Manual.
A particular apparatus of this kind is also shown in U.S. Pat. No. 4,603,114 "Method for the Sequential Performance of Chemical Processes" issues to Hood et. al. on Jul. 29, 1986. FIG. 12 of the Hood Patent illustrates a prior art manifold in which a common passage of a "sawtooth" shape is formed in the manifold block by drilling eight separate holes at angles through the thickness of the block, the separate holes coming together at openings in the top of the manifold. Each opening is positioned adjacent an input opening from a fluid source and beneath a diaphragm which will serve to valve fluid from the associated source into the common passage.
A similar arrangement is shown in U.S. Pat. No. 4,008,736 "Valve Arrangement for Distributing Fluids" issued on Feb. 22, 1037 to Wittman-Liebold et. al.
The "sawtooth" design of the common fluid passage which is evident in all of these references was utilized (in part) to solve a problem in earlier valves, in which the common passage was of a "straight-through" nature, having short sections extending perpendicularly to the common passage, in the regions below the various fluid sources. More particularly, it was found in these straight-through designs that normal cleaning cycles did not sufficiently clean the perpendicular sections, leaving undesirable residues. The sawtooth design corrected this problem, but introduced new complexities, including unsuitability for use with valve blocks of multilayer ceramic construction.